Step 1: Understanding Article 15 of the Indian Constitution.
Article 15 of the Indian Constitution prohibits discrimination against any citizen on the grounds of religion, race, caste, sex, or place of birth.
Step 2: Analyzing the Article.
Article 15 guarantees the right to equality and ensures that no individual is discriminated against based on these criteria.
Step 3: Verifying the Options.
Option (1): Right to equality is a broader concept covered in Article 14.
Option (2): Article 15 specifically addresses prohibition of discrimination on the grounds mentioned in the question.
Option (3): Protection of the environment is not covered under Article 15.
Option (4): Right to freedom of speech is part of Article 19.